Conventionally, there have been fiber reinforced composite materials that contain a three-dimensional fabric (three-dimensional fiber structure) as a fiber reinforced composite material, which is widely used as a light structural material. The fiber reinforced composite material has great strength and is used as a structural material of an airplane. There has been a following manufacturing method of the three-dimensional fiber structure that is used for a reinforcing material of the fiber reinforced composite material. A plurality of fiber bundle layers, in each of which the fiber bundles are arranged so as to be folded back, are stacked so as to form a stacked fiber bundle group that has at least biaxial orientation. The fiber bundle layers of the stacked fiber bundle group are connected to each other by connection yarns which are arranged along a direction perpendicular to each fiber bundle layer. Patent Document 1 discloses a fiber bundle arranging apparatus, in which, while a fiber bundle is let out from a guide pipe that moves along an arrangement surface, each fiber bundle is arranged in a flat state between pins that are arranged by a predetermined pitch and each fiber bundle is arranged to be folded back such that the flat surface of the fiber bundle lies along the arrangement surface to form a fiber bundle layer. Connection yarns are inserted to the stacked fiber bundle group that is formed by stacking a plurality of fiber bundles after the stacked fiber bundle group is removed from the fiber bundle arranging apparatus.
Patent Document 2 discloses an apparatus that inserts connection yarns to the stacked fiber bundle group. The apparatus disclosed in Patent Document 2 has a mechanism that inserts a retaining thread that prevents the inserted connection yarns from coming off the stacked fiber bundle group. A needle for receiving the retaining thread is engaged with a power transmission portion of a device that drives the needle for receiving the retaining thread via a damper. The power transmission portion is connected to a belt that reciprocates. When the belt reciprocates, an insertion operation (reciprocating operation) of the needle for receiving the retaining thread is executed. When the needle for receiving the retaining thread contacts a needle for receiving connection yarns or the connection yarns, an extraordinary load may be applied to the needle for receiving the retaining thread.
The damper, for example, includes a cylinder. A distal end of a plunger of the cylinder is engaged with a recess formed at a proximal end of the needle for receiving the retaining thread. If an extraordinary load is applied to the reciprocating needle for receiving the retaining thread, the distal end of the plunger is disengaged from the recess. This prevents damage of the needle for receiving the connection yarns or the needle for receiving the retaining thread.
When the guide pipe of the fiber bundle arranging apparatus moves, the guide pipe may be caught on the arranged fiber bundle, or the guide pipe may contact the pin, or an extraordinary tensile force may be applied to the fiber bundle that is being let out from the guide pipe. In this case, the guide pipe may be damaged. However, neither one of Patent Document 1 nor 2 discloses means for preventing the above problems.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2007-16347
Patent Document 2: Japanese Laid-Open Patent Publication No. 2004-256943